Projection objective for photo mechanisms



SR 5mm B M 0R 3 0 1 5 #25 I l T W 5 H5; 2 if Aug. 18, 1964 M. J. B UZAWA 3,145,255 PROJECTION OBJECTIVE FOR PHOTO MECHANISMS I z 2 6 FiledApril 25, 1952 X 2 d 4 FIG. I

E.EL.= 220.5- /45 AT INFIN. F.|-'.=|54.0 B.F.=l73.5 LENS RADIUSTHICKNESS SPACES I t 5.50 5 1.00 |.5|'r 04.5

III R5 395 4 t 5.8l L573 42.5

I R, 50,793 t,:,= l6.02 l.5l7 64.5

INVENTOR. MICHAEL J. BUZAWA AT TORNE Y United States Patent 3,145,255PROJECTION OBJECTIVE FOR PHOTO MECHANISMS Michael J. Buzawa, Rochester,N.Y., assignor to Bausch &

Lomb Incorporated, Rochester, N.Y., a corporation of New York Filed Apr.26, 1962, Ser. No. 190,369 5 Claims. (CI. 88-57) This invention relatesto*a projection objective and more particularly it relates to animprovedGauss type of optical system therefor'which is nearly symmetrical inform and is used with certain specified wavelength bands of lightinvolving only low magnification of the'object.

Optical systems of the above-mentioned type are particularly adapted foruse in photomechanisms such as spot scanners etc., in which the systemis required to image sharply a mosaic of tiny spots composed offluorescent phosphors which radiate energy in a relatively narrow waveband.

It is an object of this invention to provide a novel Gauss type ofprojection optical system having a field angle of about 8, a relativeaperture for infinity of f/4.5, and working at low magnification ofabout 2.5x, said system being well corrected chromatically in thetransmission of radiant energy from phophors in the 370 mu and 460 muwavelength bands.

A further object is to provide such a device in which all monochromaticaberrations as well as coma, distortion and flatness of field are equalto high grade objectives and in which the performance is essentiallydiffractionlimited.

Further objects and advantages will be apparent in the details ofconstruction and in the particular optical properties incorporatedtherein by reference to the specification herebelow taken together withthe accompanying drawing, in which:

FIG. 1 is an optical diagram showing a preferred for of the presentinvention; and

FIG. 2 is a chart showing the constructional data for one form of saidinvention.

Generally shown at 10 in the drawing is an optical system for aprojection objective constructed according to the present inventionwherein is comprised a front meniscus lens member I which is convextoward the front, and is optically aligned with and spaced from a reardouble convex lens member VI. Optically aligned therebetween is a nearlysymmetrical pair of meniscus compound lens members which aresymmetrically spaced about a central diaphragm 11 and are composed oftwo positive is constructed so as to form a sharp and well-correctedimage in which color correction is optimized for the selected wavelengthband, said color correction being secured along with an essentiallydiffraction-limited monochromatic performance and a flat field. Saidoptical sys- 7 term 10 embodying the characteristics above described maybe constructed by the use of the ranges of constructional data given inthe table of mathematical expressions herebelow wherein the radii of thesuccessive lens surfaces are designated R to R which are relatedrespectively to lens parts I to VI as aforesaid, the axial thicknessesof (Element I) .244 .300

(Element II) (Element III) (Element IV) (Element V) (Element VI) .206.235 9 Furthermore, the refractive index value of the lens materials inlens members I and VI and of the positive lens elements II and V isexceeded more than .050 by the refractive index value of the negativelens elements III and IV. correspondingly, the lens members I and VI aswell as the lens elements II and V have an Abbe num- .ber which exceedsby more than 20.0 the Abbe number of lens elements III and IV. A v

The individual values of the lens surface radii R to R are specified bythe following table of ranges of values thereof, the minus sign denotingthose surfaces which are convex toward entrant rays:

the preceding tables.

The ranges of values for refractive index n and Abbe number 1 arespecified by the mathematical expressions given in the table herebelow:

In order to further restrict the passage of rays to the selectedwavelength band of 370 mu,

all of the air-glass surfaces of the optical system 10 are 40 4 v )=v(V)-'v (VI)=64.5

11(III)=|/ (IV) 42.5 In order to further restrict the passage of rays tothe selected Wavelength band of 460 mu, all of the air-glass surfaces ofthe optical system 10 in this form of the invention are coated with ananti-reflection coat having a maximum transmission at the above-namedwavelength. I Stated in another manner, the last-described form of theinvention is described in the chart of numerical values herebelow:

[E.F.L.=229.3. f/4.5atinfin. F.F.=154.6. B.F.=173.5]

Lens Radius Thickness Spaces 1, v

R1=11s.0a I t1=5.50 1,517 04.5

s,=1.00 R -,=48.753 II I t=15.09 1.517 64.5

R4=92.897 III t =5.81 1. 573 42.5

s,=24.50 Diaphragm S3=24.50 R5=42,073 IV zt=5.s1 1. 573 42.5

R =-l39.32 1 V 516.02 1.517 64.5

S4=0.25 R5=731.14 VI z.=5.00 1.517 64.5

Although only certain definite forms of the present in- I vention havebeen shown and described in detail, other forms are possible and changesmay be made in the details of structure thereof without departing fromthe spirit of the invention as defined in the appended claims;

I claim: k

1. An optical system of the Gauss type for a projection objectiveworking at low magnification, said system having a relative aperture aslarge as f/4.5 for infinity and, being well corrected for coloraberration for the transmission of radiant energy in the wavelengthrange from 3400 A. to 4400 A. as well as being diffraction limited inperformance,

said system consisting of a front singlet meniscus lens member, asinglet double convex member most rearwardly, and a pair ofsubstantially symmetrical compound convex-concavo lens members opticallyaligned between said front and rear members, the concave surfaces of thecompund members enclosing a diaphragm centrally therebetween, thecompound members each having a positive meniscus lens element and anegative meniscus lens element in contact therewith and nearest to saiddiaphragm, the radii R to R of the successive lens surfaces on the lenselements I to VI, vthe successive lens thicknesses t to t the lensspacings S to S and the refractive indices m; and Abbe numbers 1/ havingvalues substantially as given in the table herebelow;

3400 A. to 4400 A. as well as being diffraction limited in performance,

' said system consisting of a front singlet meniscus lens I member, asinglet double convex member most rear wardly, and a pair ofsubstantially symmetrical compound convex-concavo lens members, theconcave surfaces of the compound members enclosing a diaphragm centrallytherebetween, the compound members each having a positive meniscus lenselement and a negative meniscus lens element in contact therewith andnearest to said, diaphragm, the radii R to R of the successive lenssurfaces on the lens elements I to VI, the successive lens thicknessest, to the lens spacings S to S and the refractive indices m; and Abbenumbers 1! having values substantially as given in the table herebelow;

the air-glass surfaces thereof, said coat having a maxi mum lighttransmission at a wavelength of substantially 460 millimicrons.

5. An optical system of the Gauss type for a projection objectiveworking at low magnification, said system having a relative aperture aslarge as f/4.5 for infinity and being well corrected for coloraberration for the transmission of radiant energy in the wavelengthrange from 3400 A. to 4400 A. as well as being diffraction limited inperformance,

said system consisting of a front singlet meniscus lens member, asinglet double convex member most rearwardly, and a pair ofsubstantially symmetrical compound convex-concave lens members opticallyaligned between said front and rear members, the concave surfaces of thecompound members enclosing a diaphragm centrally therebetween, thecompound members each having a positive meniscus lens element and anegative meniscus lens element in contact therewith and nearest to saiddiaphragm, the

radii R to R of the successive lens surfaces on the Lens RadiusThickness Spaces 111, r

R ==118.03 I t =5.50 1.517 64.5

S1=L00 R;=48.753 II tz=15.09 1.517 64.5

R4=92.897 R5=39.084 III t =5.81 Rq=-42.073 Y S3=Z4.50

, Diaphragm S;=24.50 IV t =5.81 1.573 42.5

R =139.32 V ls=16.02 l. 517 64.5

'S4=O.25 Ro=731.14 VI..--.-.- is=5.00 1.517 64.5

References Cited in the file of this patent UNITED STATES PATENTS2,682,198 Aklin -a June 29, 1954 2,936,675 Schade May 17, 19 60 Lange eta1 July 10, 1962 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIONPatent No 3, 145,255 August 18, 1964 Michael J, Buzawa It is herebycertified that error appears in the above numbered patent requiringcorrection and that the said Letters Patent should read as correctedbelow.

Column 2, line 40, for "S ,OO18F read S ,OOll8F 1 column 4, in the tableunder the heading "Thickness", line 5 thereof, for "t 16.O2 read t 16O2Signed andtsealed this 29th day of December 1964.,

(SEAL) Attest:

EDWARD J. BRENNER ERNEST W. SWIDER Attesting Officer CommissioneriofPatents

1. AN OPTICAL SYSTEM OF THE GAUSS TYPE FOR A PROJECTION OBJECTIVEWORKING AT LOW MAGNIFICATION, SAID SYSTEM HAVING A RELATIVE APERTURE ASLARGE AS F/4.5 FOR INFINITY AND BEING WELL CORRECTED FOR COLORABERRATION FOR THE TRANSMISSION OF RADIANT ENERGY IN THE WAVELENGTHRANGE FROM 3400 A. TO 4400 A. AS WELL AS BEING DIFFRACTION LIMITED INPERFORMANCE, SAID SYSTEM CONSISTING OF A FRONT SINGLET MENISCUS LENSMEMBER, A SINGLET DOUBLE CONVEX MEMBER MOST REARWARDLY, AND A PAIR OFSUBSTANTIALLY SYMMETRICAL COMPOUND CONVEX-CONCAVO LENS MEMBERS OPTICALLYALIGNED BETWEEN SAID FRONT AND REAR MEMBERS, THE CONCAVE SURFACES OF THECOMPOUND MEMBERS ENCLOSING A DIAPHRAGM CENTRALLY THEREBETWEEN, THECOMPOUND MEMBERS EACH HAVING A POSITIVE MENISCUS LENS ELEMENT AND ANEGATIVE MENISCUS LENS ELEMENT IN CONTACT THEREWITH AND NEAREST TO SAIDDIAPHRAGM, THE RADII R1 TO R10 OF THE SUCCESSIVE LENS SURFACES ON THELENS ELEMENTS I TO VI, THE SUCCESSIVE LENS THICKNESSES T1 TO T6, THELENS SPACINGS S1 TO S4 AND THE REFRACTIVE INDICES ND AND ABBE NUMBERS VHAVING VALUES SUBSTANTIALLY AS GIVEN IN THE TABLE HEREBELOW; R1=.497FR2=1.773F R3=.204F R4=.414F R5=.167F R6=-.1785F R7=-.609F R8=-.2135FR9=4.140F R10=-.657F T1=.0254F T2=.0595F T3=.0254F T4=.0245F T5=.0631FT6=.0233F S1=.00424F S2=.1063F DIAPHRAGM S3=.1063F S4-.000833FND(I)=ND(II)=ND(V)=ND(VI)=1.517 ND(II)=ND(IV)=1.583V(I)=V(II)=V(V)=V(VI)=64.2 V(III)=V(IV)=46.5